This invention relates to improved immunoassays of psychotomimetic drugs, narcotic drugs, tetrahydrocannabinols and other psychoactive drugs.
At the present time, there are certain methods used for the determination of psychotomimetic and narcotic drugs in biological materials.
The techniques that are used in the present time for the determination of drugs in biological materials, are described in detail in the Handbook of Analytical Toxicology (Irving Sunshine, Editor; The Chemical Rubber Company, Publisher; Cleveland, Ohio, 1969). They include in different combination for the different drugs: paper, thin layer and gas-liquid chromatographic methods, crystal tests, fluorescence, infrared, ultraviolet, thermal microscopy and animal pharmacology studies.
In general, the tests are time consuming, expensive, require expensive equipment, and require well trained personnel. Some of the tests are not sensitive, others lack high specificity. Special difficulty is encountered in the determination of one drug in the presence of other drugs in the same biological material specimen. Thus heroin is difficult to determine in the urine in the presence of nicotine, as disclosed by D. J. Berry et al in xe2x80x9cThe Detection of Drugs of Dependence in Urinexe2x80x9d (Bulletin on Narcotics 22, No. 3, July-September 1970; United Nations Publication). Tetrahydrocannabinols are difficult to determine in the presence of barbiturates, and complicated methods are needed for their determination in the presence of barbiturates, as described by Harold V. Street in xe2x80x9cIdentification of Drugs by a Combination of Gas-Liquid, Paper and Thin-Layer Chromatographyxe2x80x9d (Journal of Chromatography 48, 291-4, 1970).
The methods of the present invention have the advantages of simplicity, speed, specificity and low cost. They also have the advantage of being able to be applied xe2x80x9con the spotxe2x80x9d (e.g. emergency room of a small field hospital). Van Vunakis et al (xe2x80x9cProduction and Specificity of Antibodies Directed towards 3,4,5-Trimethoxy-phenyl-ethylamine, and 2,5-Dimethoxy-4-methylamphetamine,xe2x80x9d Bioch. Pharmacol. 18, 393-404, 1969) were able to obtain high specificity and sensitivity in their determination, by microcomplement fixation inhibition or 3,4,5-Trimethoxy-phenylethylamine and congeners, as well as 2,5-Dimethoxy-4-Methylamphetamine and congeners. Micro-complement-fixation-inhibition is however a complicated method. Reagents have to be prepared freshly for each experiment, and they require specially trained personnel. In the methods hereinafter to be described, no such limitations are present.
The length of time required by presently known procedures for determining psychoactive drugs also severely limits their usefulness in clinical applications.
The invention also includes immunological methods for the treatment of drug intoxication; the treatment and prevention of drug addiction, drug dependence and drug abuse; and the treatment of schizophrenia. The need for treatment methods for intoxication by psychoactive drugs, methods for freeing persons dependent on such drugs from their dependence, and methods of treating schizophrenia has long been felt. The present methods provide attractive and useful approaches to all of these needs.
In accordance with this invention, generally stated, diagnostic and treatment methods are provided by the use of the haptenic properties of psychoactive material. The term xe2x80x9cpsychoactivexe2x80x9d includes psychotomimetic compounds containing an indol ring such as N,N-Dimethyltryptamine and its congeners and LSD 25 and its congeners; amphetamines and their congeners; narcotics such as phenanthrene alkaloids (such as morphine, heroin, codeine, hydromorphone, and levorphanol) and nonphenanthrene alkaloids (such as meperidine, methadone, and phenazocine); and tetrahydrocannabinols and other cannabinoids.
A hapten may be defined as any small molecule which by itself does not produce antibodies but which, when conjugated to a carrier protein or other macro-molecular carrier, induces in the recipient animal or human the production of antibodies which are specific to the small molecule.
The present invention is based in part upon the application of known immunoassay techniques for haptens to certain psychoactive compounds which have not heretofore been recognized as haptens (such as N,N-dimethyltryptamine and congeners, and tetrahydrocannabinols and their congeners); in part upon the discovery of methods of adapting techniques which were heretofore used only for the determination of antibodies or complete antigens to techniques for determining haptens; in part upon the discovery of immunological treatment methods for such seemingly disparate medical problems as drug intoxication, drug dependence and schizophrenia; and in part upon the development of entirely new methods for the treatment of drug intoxication based in part upon the haptenic characteristics of the intoxicating drugs.
The discovery that 5-methoxy-N,N-dimethyltryptamine and congeners are haptens and the recognition that tetrahydrocannabinols(such as delta-9-tetrahydrocannabinol) are haptens, permits their determination by known immunoassay methods for haptens, such as radioimmunoassay (Spector et al, Science 168, page 1347, 1970; Niswender et al, in Immunological Methods in Steroid Determination, edited by Peron and Caldwell, 1970, pages 149-173) and micro-complement fixation inhibition (Levine, in Handbook of Experimental Immunology, edited by D. M. Weir, 1967, pages 707-719, especially page 712). These psychoactive haptens also may be utilized in the determination of their antibodies by methods such as those described in Handbook of Experimental Immunology (ed. Weir), pages 423-968, for example hemagglutination (W. J. Herbert xe2x80x9cPassive Hemagglutinationxe2x80x9d in Handbook of Experimental Immunology, pages 720-744).
The invention also encompasses the determination of haptens, and particularly psychoactive haptens, by simple and accurate agglutination and agglutination-inhibition assays.
The agglutination inhibition assay includes the steps of mixing a sample containing an unknown quantity of psychoactive hapten with a predetermined quantity of an antibody to the hapten, and then combining this mixture with a predetermined quantity of the hapten bound to an agglutinable particulate carrier. Presence of a sufficient amount of the psychoactive hapten in the sample will inhibit hemagglutination. The usual tray or other equipment may be utilized to obtain a quantitive measure of the psychoactive hapten (Handbook of Experimental Immunology, pp 782-785).
The agglutination methods involve the binding of an antibody to an agglutinable particulate carrier. This binding may require the use of a chemical binding technique such as the bis-diazotized-benzidine (BDB) technique. These techniques are set out in Handbook of Experimental Immunology, pages 737-740, Cua-Lim et al, J. Allergy 34, 142 (1963); Ingraham, Proc. Soc. Exp. Biol., N.Y. volume 99, 452 (1958).
These agglutinable carrier-bound antibodies may be used in a number of agglutination procedures. In one, a sample is mixed with the agglutinable carrier-bound antibody in suspension, the agglutinable carrier-antibody is then mixed with a free antibody to the hapten. If the sample contains above a minimal amount of the free hapten, agglutination will result. In another method antibodies to two different sites on the hapten are prepared and bound to an agglutinable particulate carrier. Addition of a sample which contains the free hapten produces agglutination. Other procedures utilizing two different antibodies to two different sites on the hapten may be provided in which only one, or neither, of the antibodies is bound to an agglutinable particulate carrier.
In all of the agglutination and agglutination inhibition procedures, erythrocytes (red blood cells) are the presently preferred carrier. The erythrocyte may or may not be treated, for example by formalin treatment (Ingraham, supra). However, other agglutinable material such as latex or other particles may be useful in some or all of the methods.
The invention also encompasses the passive immunizationfor drug (hapten) intoxication. It is particularly directed to in vitro immunotherapy methods through immuno-dialysis or immuno-adsorbtion techniques. It also may be applied to auto-intoxication by substances etiological to diseases such as schizophrenia. For example, recent research indicates that N,N-dimethylated-indoleamines are psychotomimetic agents which are etiological to schizophrenia. See for example Tanimukai et al in Recent Advances in Biological Psychiatry, volume 10, pages 6-15 (1968); Narasimhachari et al in Biological Psychiatry volume 3, pages 21-23 (1971). Therefore, one treatment method includes the passive immunization of schizophrenic patients with antibodies to N,N-dimethylated-indoleamines. Antibody fragments may also be used. The treatmnet of species which are etiological to schizophrenia and also are complete antigens may include the step of splitting the antibodies (for example by the method set out in Boyd, Fundamentals of Immunology (4th edition, 1966), especially at pages 70-71 in order to prevent precipitation of the species. The active immunization procedure may be used both in schizophrenia, by administration of an antigen which produces antibodies to a species which is etiological to schizophrenia (for example a protein conjugate of N,N-dimethyltryptamine), or in the treatment of drug dependent persons. The treatment includes administration of an antigen (or antigens) which produces antibodies to the drug (or drugs) on which the individual is dependent.